The performance of a road-going vehicle is limited, in part, by the level of traction between tires of the vehicle and the road surface on which the vehicle travels. All other parameters being equal, with more traction, a vehicle can accelerate, change direction, and stop more quickly. Traction between the tires and the road surface is directly proportional to the friction between the tires and the road surface, which, in turn, is directly proportional to the coefficient of friction between the tires and the road surface. The coefficient of friction is largely a function of characteristics of the material and tread of the tires and characteristics of the road surface, such as, for example, the material and texture of the road surface and any coating on the road surface, such as, for example, dirt, oil, water, snow, or ice.
Aside from purely mechanical limitations, however, vehicle acceleration may also be intentionally limited for occupant comfort and safety. Modern fighter jets, for example, can maneuver at acceleration high enough to cause pilots to lose consciousness and even to cause pilot injury or death. Thus, while a pilot may call for maximum lateral acceleration during a dogfight, for example, the acceleration of the plane is generally computer-limited to acceleration levels that can be tolerated by the pilot (i.e., as opposed to being governed by the structural limits of the aircraft). Airliners and cruise ships, on the other hand, generally maneuver as slowly and smoothly as possible to avoid causing passenger discomfort and motion sickness, among other things. Similarly, current autonomous emergency braking systems and adaptive cruise control systems are limited to around 9 m/s2 and 4.5 m/s2, respectively, of acceleration—e.g., positive, negative (braking), lateral, or a combination thereof—for passenger comfort and safety. This can prevent passengers from being unnecessarily thrown about the interior of the vehicle or experiencing motion sickness, among other things.